Flask



FIG. 1 is a top plan view of the flask showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top, rear, and left side perspective view thereof;

FIG. 5 is a top, front, and right side perspective view thereof; and,

FIG. 6 is a right side elevational view thereof, the left side elevational view being a mirror image. 

The ornamental design for a flask, as shown and described. 